1. Field of the Invention
This invention relates to Manufacturing machinery for conveying cylindrical containers to and from stations or indexing points where the container's movement is stopped for a fixed period of time but specifically to feed screws for conveying the containers to and from the aforementioned stations. Machines for carrying out this conveyance system are widespread and in common use in various applications. These include: container inspection, container labeling, container internal coating and external coating, and in many other process applications. The aforementioned processes are applied or performed upon the containers indexed at process stations described by the conveyance mechanism wherein the container stops its progress, is indexed for a certain dwell time and thereafter, once the progress has been completed, the container is moved away from the station.
2. Prior Art
Relative to a specific application mentioned further herein, prior art internal spray coating machines incorporate roller cam indexing units to impart intermittent motion to the container in order to allow sufficient dwell time for the spraying operation. The indexing units are equipped with turrets containing approximately six pockets to accept and accurately deliver the can to the spray position. Such a machine is disclosed in the U.S. patent to Pierson, U.S. Pat. No. 2,341,477. The turrets weight approximately 15 to 18 lbs. and are one of the limiting factors in being able to obtain higher operating speeds. For example, in such a spray machine which would normally be rated at 150 to 200 cans per minute the roller cam indexing units are not capable of higher inertial loads exerted on the cam rollers and bearings which generally fatigue within a few months to a year of continuous 24 hour service.